Three Appeal Court judges in Belfast were asked yesterday to decide a test case linked to the controversy over whether journalists have a right not to reveal their sources.
The case relates to the Bloody Sunday inquiry and the refusal of the Daily Telegraph's former Ireland correspondent Toby Harnden to identify a former member of the Parachute Regiment.
The ex-soldier was on duty in Derry on January 30th, 1972, when 13 civilians were shot dead by paratroopers and his recollection formed the basis of a story in the newspaper on May 20th, 1999.
Mr Harnden's reason for refusing to co-operate with Lord Saville's inquiry was an undertaking he gave the soldier - known as X - that he would not say or do anything which might reveal his identity
He told the inquiry in a written statement that within a few days of the story appearing all records were destroyed.
Mr Harnden, now based in Washington, said the normal journalistic practice would be to preserve such records.
But he had decided to destroy them so as to prevent any subsequent disclosure to the inquiry which would constitute a breach of trust between a journalist and his sources as well as running counter to his assurances of confidentiality.
Lord Saville held that Mr Harnden was in contempt and referred the matter to the High Court in Belfast, which could have resulted in him being jailed for up to two years.
But when the case came before Mr Justice Coghlin there was a protracted legal argument as to whether the contempt proceedings were criminal in nature, which would afford Mr Harnden additional legal rights at his trial, or if they were of a civil character, as contended by Lord Saville's lawyers.
The judge ruled that having regard to the right to a fair trial, as enshrined in the European Convention, the proceedings should be regarded as criminal.
Lord Saville appealed the judge's ruling yesterday before the Lord Chief Justice, Sir Robert Carswell, Lord Justice Nicholson and Lord Justice Campbell.
During the course of legal arguments, the issue of jurisdiction arose and it was suggested that the original hearing before Mr Justice Coghlin should have taken place before a Divisional Court consisting of two judges.
Any appeal from such a court would bypass the Court of Appeal and go direct to the House of Lords.
The Appeal Court judges will rule on this point today but if they decide to go ahead and finish the appeal they are expected to reserve their decision.
Legal sources said the issues were so important that no matter what happens the case is almost certain to go to the House of Lords and could end up in the European Court of Human Rights in Strasbourg.